Practice Assignment 3

[Ruchi Sinha]

8) If the mean of the observations x1,x2,x3,⋅⋅⋅,xnx1,x2,x3,···,xn is 15, the mean of the observations x1,x2,x3,⋅⋅⋅,x2nx1,x2,x3,···,x2n is 45, and the mean of the observations x1,x2,x3,⋅⋅⋅,x3nx1,x2,x3,···,x3n is 34, then what is the mean of the observations 2xn+1,2xn+2,2xn+3,⋅⋅⋅,2x2n,3x2n+1,3x2n+2,3x2n+3,⋅⋅⋅,3x3n2xn+1,2xn+2,2xn+3,···,2x2n,3x2n+1,3x2n+2,3x2n+3,···,3x3n?

I have a doubt in this (see attached image) that why is the whole equation divided by 2n and not 3n?

[Statistics 1 Support 1]

Hi,

Count the number of observations you are adding. observations are x(n+1), x(n+2), .. up to x(3n). These are 2n observations. That's why 2n will be there in the dinominator.

Thanks,

Nitin Jha

Course support team